1. Field of the Invention
The invention disclosed herein relates to a temperature sensor, and in particular, to a combined temperature and pressure sensor that may be mounted onto a variety of apparatus for sensing temperature and pressure.
2. Description of the Related Art
A variety of industrial processes call for knowledge of ambient temperature and pressure conditions. For example, in automotive systems, it is desirable to know pressure and temperature of gasses so that combustion may be more efficiently controlled. A number of sensors have been devised to address this need.
Generally, these sensors provide for monitoring of at least one of temperature and pressure on an ongoing basis. In some embodiments, the sensors are adapted for harsh environments. As one might surmise, some of these sensors are complicated (and therefore costly) devices.
Consider for example, U.S. Pat. No. 8,038,345, entitled “Sensor plug for combined pressure and temperature measurement,” which issued on Oct. 18, 2011 to Stoll et al. This patent discloses a sensor plug for pressure and temperature measurement of a fluid medium. The sensor plug includes a sensor body having a sensor body axis, as well as a pressure sensor disposed substantially concentrically on the sensor body axis. Also provided in the sensor body is a through orifice for connecting the pressure sensor to the fluid medium, and a temperature sensing element orifice having a temperature sensing element received therein. The temperature sensing element orifice has a temperature sensing element orifice axis that is inclined with respect to the sensor body axis in such a way that at its end pointing toward the fluid medium, it is inclined toward the sensor body axis.
Unfortunately, this device is relatively complicated to assemble. For example, a laser welding process is used “which must meet stringent requirements.” Accordingly, it is anticipated that assembly is costly, time consuming, and may result in a number of defective units.
Consider another device described in U.S. Pat. No. 7,467,891, entitled “Sensor arrangement for measuring a pressure and a temperature in a fluid,” which issued on Dec. 23, 2008 to Gennissen, et al. This patent discloses a sensor arrangement for measuring a pressure and a temperature in a fluid. The sensor arrangement includes a temperature sensitive electrical element and a pressure sensing electrical element, the temperature sensitive electrical element and pressure sensing electrical element are both coupled to one side of a metallic membrane structure.
Similar to the sensor plug of Stoll et al., the sensor arrangement of Gennissen, et al. includes multiple and separate sensing elements, and may therefore be complicated to assemble.
Given that sensors are often used in large quantities, such as in mass-produced automobiles, it is desirable to have a robust sensor that may be easily and reliably manufactured. Thus, what is needed is a design for a sensor that provides for simple, cost effective manufacture and results in reliable performance.